Poster Presentation

Sgr A* observations with KaVA and EAVN

Author(s): G. -Y., Zhao (KASI); M., Kino (NAOJ); K., Akiyama (Haystack); B. W., Sohn (KASI); T., Jung (KASI); I. -J., Cho (KASI); W., Jiang (SHAO); Z. -Q., Shen (SHAO); and the KaVA/EAVN AGN working group

Presenter: Guang-Yao Zhao (Korea Astronomy and Space Science Institute)

In this presentation, we will summarize recent observational results of Sgr A* obtained with KaVA Long-term monitoring at 7 mm which is part of the KaVA/EAVN AGN large program. The KaVA array provides an excellent (u,v)-coverage for Sgr A* observations, especially alone the minor axis direction. The source is in a relatively quiescent status during our KaVA monitoring. No sign of G2 encounter has been detected so far, which supports the predictions of delayed or no activity from the close encounter. We found the sizes of Sgr A* is very stable during the several years of monitoring, which enables us to put tight constraints on the physical parameters of the scattering screen. We also show that joint observations at 13 and 7 mm with more stations in the East Asia region and the KaVA array (EAVN) can further enhance the image quality (uv-coverage, sensitivity) and more explorations could be possible.